Technology Of Error Detection&Correction Coding And Decoding In Satellite Image Lossless Compression

Bandwidth resources in wireless communication systems is limited, in order to obtainhigher image wireless transmission efficiency, digital images must be compressed.Codestream of compressed digital image has a very strong correlation, it is very sensitive tochannel bit error, code word in decoding is easy to lose synchronization, resulting in errorpropagation. Due to the variability of the wireless communication channel, it is impossibleto achieve completely reliable data transmission. Technology of error resilient protectingand error detection and correction coding in compressed image wireless transmitting is thesignificance of the research topic.Channel coding is effective to reduce the influence of channel errors on the wirelesstransmission of the image, this paper in-depth study the error resilience theory oflow-density parity coding (LDPC), it implements the CCSDS standard (8176,7154) LDPCcode, analyses LDPC code’s error correction performance and error distribution law,builds the channel simulation and error injection model.In order to meet the needs of error resilience protection in sources, this paper presentstwo error resilience strategy which are the block error detection coding andtwo-dimensional parity check coding mixed interleaving technology. Block error detectioncoding based on image block coding, error block can be detected according to code streammulti-dimensional characteristics in the image reconstruction, meanwhile errorpropagation can be effectively controlled by block error detection code and the entropydecoding.According to the (8176,7154) LDPC code error distribution law, channel errorcan be dispersed evenly to the whole stream by interleaved coding, then use thetwo-dimensional parity code to correct independent bit errors in stream.According to the research of source compression coding, source error detection andcorrection coding, LDPC channel coding, this paper presents a joint source/channel codingand decoding method. This method is composed of source compression coding, sourceerror detection and correction coding, interleaved coding and LDPC channel coding. It isbased on the error distribution law of the different channel conditions, each encoding algorithm has been optimized. Experiments show that the joint source/channel coding anddecoding method has excellent image data compression and error resilience performance.